( after only a few years. The need for be...)Secrets of the sea yield stronger artificial bone

after only a few years. The need for better biomaterials is further underscored by the growing demand for artificial joints. More than 150,000 hip replacement and nearly 300,000 knee replacements were performed in 2000, according to the National Center for Health Statistics. These numbers are expected to swell in the future as baby boomers age.

Because of the pressing need for longer-lasting artificial bone, researchers like Tomsia have developed materials that take their cue from nature. In this case, Tomsia and colleagues turned to the ocean. When seawater freezes, crystals of pure ice form layers, while impurities such as salt and microorganisms are expelled from the forming ice and entrapped in channels between the ice crystals. The result is a layered structure that roughly resembles nacre's wafer-like construction.

The Berkeley Lab team believed this same freezing process could be used to cast an exquisitely layered material that comes close to mimicking nacre's toughness and lightness. They created a watery suspension of hydroxyapatite, which is the mineral component of bone. Then, they froze it. Just like the impurities in sea ice, the hydroxyapatite concentrates in the space between the ice crystals, creating layers and layers of nacre-like material.

They also found that by increasing the rate of this freezing process, the layered structure reduces in scale. Ultimately, they obtained a microstructure that measures one micron, or one-millionth of a meter. In comparison, nacre's structure measures half of a micron.

"We are half a micron away from mimicking nature," says Tomsia.

After the ice is removed via sublimation, the result is a porous scaffolding composed of hydroxyapatite that exhibits striking similarities to nacre's multilayered structure across a wide range of length scales. Like nacre, the surface of each layer is rough, helping the layers lock in place with whatever substance fills the space between them. A
'"/>

Source:DOE/Lawrence Berkeley National Laboratory

Page: 1 2 3 4
Related biology news :

1. Weill Cornell Research Reveals Secrets Of Trafficking Within Cells
2. Secrets to antibodys success against West Nile Virus surprise scientists
3. Secrets of the deep may hold key to life on other planets
4. Genome-wide mouse study yields link to human leukemia
5. Microbial fuel cell: High yield hydrogen source and wastewater cleaner
6. Insight into DNAs weakest links may yield clues to cancer biology
7. Marine sponge yields nanoscale secrets
8. New understanding of cell movement may yield ways to brake cancers spread
9. Small worm yields big clue on muscle receptor action
10. Modified collagen could yield important medical applications
11. Elderly mice yield clues to the process of growing old